import * as path from 'path'; import * as vscode from 'vscode'; // Reference: // https://github.com/rust-lang/rust/blob/master/src/libsyntax/json.rs export interface RustDiagnosticSpan { line_start: number; line_end: number; column_start: number; column_end: number; is_primary: boolean; file_name: string; label?: string; suggested_replacement?: string; suggestion_applicability?: | 'MachineApplicable' | 'HasPlaceholders' | 'MaybeIncorrect' | 'Unspecified'; } export interface RustDiagnostic { spans: RustDiagnosticSpan[]; rendered: string; message: string; level: string; code?: { code: string; }; children: RustDiagnostic[]; } export interface MappedRustDiagnostic { location: vscode.Location; diagnostic: vscode.Diagnostic; codeActions: vscode.CodeAction[]; } interface MappedRustChildDiagnostic { related?: vscode.DiagnosticRelatedInformation; codeAction?: vscode.CodeAction; messageLine?: string; } /** * Converts a Rust level string to a VsCode severity */ function mapLevelToSeverity(s: string): vscode.DiagnosticSeverity { if (s === 'error') { return vscode.DiagnosticSeverity.Error; } if (s.startsWith('warn')) { return vscode.DiagnosticSeverity.Warning; } return vscode.DiagnosticSeverity.Information; } /** * Converts a Rust span to a VsCode location */ function mapSpanToLocation(span: RustDiagnosticSpan): vscode.Location { const fileName = path.join(vscode.workspace.rootPath!, span.file_name); const fileUri = vscode.Uri.file(fileName); const range = new vscode.Range( new vscode.Position(span.line_start - 1, span.column_start - 1), new vscode.Position(span.line_end - 1, span.column_end - 1) ); return new vscode.Location(fileUri, range); } /** * Converts a secondary Rust span to a VsCode related information * * If the span is unlabelled this will return `undefined`. */ function mapSecondarySpanToRelated( span: RustDiagnosticSpan ): vscode.DiagnosticRelatedInformation | undefined { if (!span.label) { // Nothing to label this with return; } const location = mapSpanToLocation(span); return new vscode.DiagnosticRelatedInformation(location, span.label); } /** * Determines if diagnostic is related to unused code */ function isUnusedOrUnnecessary(rd: RustDiagnostic): boolean { if (!rd.code) { return false; } return [ 'dead_code', 'unknown_lints', 'unused_attributes', 'unused_imports', 'unused_macros', 'unused_variables' ].includes(rd.code.code); } /** * Converts a Rust child diagnostic to a VsCode related information * * This can have three outcomes: * * 1. If this is no primary span this will return a `noteLine` * 2. If there is a primary span with a suggested replacement it will return a * `codeAction`. * 3. If there is a primary span without a suggested replacement it will return * a `related`. */ function mapRustChildDiagnostic(rd: RustDiagnostic): MappedRustChildDiagnostic { const span = rd.spans.find(s => s.is_primary); if (!span) { // `rustc` uses these spanless children as a way to print multi-line // messages return { messageLine: rd.message }; } // If we have a primary span use its location, otherwise use the parent const location = mapSpanToLocation(span); // We need to distinguish `null` from an empty string if (span && typeof span.suggested_replacement === 'string') { const edit = new vscode.WorkspaceEdit(); edit.replace(location.uri, location.range, span.suggested_replacement); // Include our replacement in the label unless it's empty const title = span.suggested_replacement ? `${rd.message}: \`${span.suggested_replacement}\`` : rd.message; const codeAction = new vscode.CodeAction( title, vscode.CodeActionKind.QuickFix ); codeAction.edit = edit; codeAction.isPreferred = span.suggestion_applicability === 'MachineApplicable'; return { codeAction }; } else { const related = new vscode.DiagnosticRelatedInformation( location, rd.message ); return { related }; } } /** * Converts a Rust root diagnostic to VsCode form * * This flattens the Rust diagnostic by: * * 1. Creating a `vscode.Diagnostic` with the root message and primary span. * 2. Adding any labelled secondary spans to `relatedInformation` * 3. Categorising child diagnostics as either Quick Fix actions, * `relatedInformation` or additional message lines. * * If the diagnostic has no primary span this will return `undefined` */ export function mapRustDiagnosticToVsCode( rd: RustDiagnostic ): MappedRustDiagnostic | undefined { const codeActions = []; const primarySpan = rd.spans.find(s => s.is_primary); if (!primarySpan) { return; } const location = mapSpanToLocation(primarySpan); const secondarySpans = rd.spans.filter(s => !s.is_primary); const severity = mapLevelToSeverity(rd.level); const vd = new vscode.Diagnostic(location.range, rd.message, severity); vd.source = 'rustc'; vd.code = rd.code ? rd.code.code : undefined; vd.relatedInformation = []; for (const secondarySpan of secondarySpans) { const related = mapSecondarySpanToRelated(secondarySpan); if (related) { vd.relatedInformation.push(related); } } for (const child of rd.children) { const { related, codeAction, messageLine } = mapRustChildDiagnostic( child ); if (related) { vd.relatedInformation.push(related); } if (codeAction) { codeActions.push(codeAction); } if (messageLine) { vd.message += `\n${messageLine}`; } } if (isUnusedOrUnnecessary(rd)) { vd.tags = [vscode.DiagnosticTag.Unnecessary]; } return { location, diagnostic: vd, codeActions }; }